Currently, there is an expanding demand for vegetable and fruit products with roasted flavor and color characteristics. The uses for the resultant products are targeted towards food service, food manufacturing, and food ingredient companies, for various food applications, such as pre-cooked meals and toppings for fast food products. Such products will have roasted characteristics, long term storage capability, comparatively high flavor retention, and minimal syneresis. Roasted products can further be frozen for transportation and shipped in bags as frozen and ready to use. When the bag is opened, after thaw, there should be a minimal amount of water present in the bag.
Traditionally, to roast a vegetable or fruit, such as an onion, it was necessary to expose the onion to a heating device for a prolonged exposure until the roasted characteristics such as roasted flavor and coloring developed. Most natural or untreated vegetable or fruit products typically have high moisture content (above 90% moisture). The comparatively high moisture content increases the exposure time required, in traditional roasting devices, to produce the resultant roasted characteristics in the vegetable or fruit. Because traditional roasting methods require extended exposure to the flame, there is a higher amount of fuel consumption, resulting in higher overall costs for producing the roasted product. As such, it is desired to have a method for producing large quantities of roasted vegetable or fruit food products that are not labor-intensive and do not require extended exposure to the roasting device.
Current methods employed in the industry use a heating device to roast the fresh vegetable or fruit followed by individually quick freezing (IQF) or refrigeration. This traditional roasting method requires extending exposure to the heating device before the food particle develops suitable roasted appearance, flavor, aroma, and texture. As a result of the extended exposure to the heating element, increased fuel consumption is required to power the heating element and whereby causing a decrease in industrial efficiency. Additionally, the roasted food product of traditional roasting methods lack consistency because increased exposure to the flame can cause uneven surface charring of the food product and inhibit a uniform roasted flavor and texture. The prolonged exposure to the flame can result in the outer surface being charred or burnt before the interior flesh of the food product can produce the roasted flavor. The uneven charring and burnt surface decreases the appeal for consumers because of the residual burnt or carbon flavor associated with a food product that has been overcooked. As such, it is desired to have a method for rapidly exposing a vegetable or fruit food product to a roasting device to form a resultant roasted food product with uniform concentrated flavors, increased consumer appeal, and increased roasting efficiencies due to reduced heating exposure.
Another problem associated with traditional processed roasted vegetable and fruit food products that are frozen for future use, is the loss of cell wall integrity leading to syneresis upon thawing. Syneresis causes a typical frozen roasted vegetable or fruit food product to exhibit an undesirable mushy texture upon thawing. Syneresis is a result of cell wall degradation that leads to leaching of moisture typically contained within the cell of a vegetable or fruit. Traditional IQF roasted vegetable and fruit food products exhibit elevated moisture levels, which lead to cell structure degradation when the consumer subsequently thaws the frozen processed roasted vegetable or fruit food product. Thus, it is further desired to have a method that can produce a roasted vegetable or fruit food product with robust roasted flavor, minimal syneresis, increased cell wall integrity, and decreased moisture content.